Systems and methods for providing power management

ABSTRACT

A network device includes one or more memories and one or more processor circuits coupled to the one or more memories. The one or more processor circuits are configured to cause providing for transmission a request directed to a network controller to change a power state of the network device, receiving a grant from the network controller in response to the request, and changing the power state of the network device in response to receiving the grant. The power state of the network device includes a running power state and a standby power state, where the standby power state includes an active mode and an idle mode. A network controller for granting a request from the network device to change a power state of the network device is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/511,165, filed on Jul. 29, 2009, entitled “Systems and Methods forProviding a MoCA Power Management Strategy,” which in turn claimspriority from U.S. Provisional Patent Application No. 61/085,096, filedJul. 31, 2008, entitled “Systems and Methods for Providing a MoCA PowerManagement Strategy” and U.S. Provisional Patent Application No.61/187,616, filed on Jun. 16, 2009, entitled “MoCA Power Management,”each of which is hereby incorporated by reference in its entirety forall purposes.

FIELD OF TECHNOLOGY

The present disclosure relates generally to information networks and, inparticular, to systems and methods for providing power management.

BACKGROUND

Home network technologies using coax are known generally. The Multimediaover Coax Alliance (MoCA™), at its website mocalliance.org, provides anexample of a suitable specification (MoCA 1.1) for networking of digitalvideo and entertainment through existing coaxial cable in the home whichhas been distributed to an open membership.

Home networking over coax taps into the vast amounts of unused bandwidthavailable on the in-home coax. More than 70% of homes in the UnitedStates have coax already installed in the home infrastructure. Many haveexisting coax in one or more primary entertainment consumption locationssuch as family rooms, media rooms and master bedrooms—ideal fordeploying networks. Home networking technology allows homeowners toutilize this infrastructure as a networking system and to deliver otherentertainment and information programming with high QoS (Quality ofService).

The technology underlying home networking over coax provides high speed(270 mbps), high QoS, and the innate security of a shielded, wiredconnection combined with state of the art packet-level encryption. Coaxis designed for carrying high bandwidth video. Today, it is regularlyused to securely deliver millions of dollars of pay per view and premiumvideo content on a daily basis. Home networking over coax can also beused as a backbone for multiple wireless access points used to extendthe reach of wireless network throughout a consumer's entire home.

Home networking over coax provides a consistent, high throughput, highquality connection through the existing coaxial cables to the placeswhere the video devices currently reside in the home. Home networkingover coax provides a primary link for digital entertainment, and mayalso act in concert with other wired and wireless networks to extend theentertainment experience throughout the home.

Currently, home networking over coax works with access technologies suchas ADSL and VDSL services or Fiber to the Home (FTTH), that typicallyenter the home on a twisted pair or on an optical fiber, operating in afrequency band from a few hundred kilohertz to 8.5 MHz for ADSL and 12Mhz for VDSL. As services reach the home via xDSL or FTTH, they may berouted via home networking over coax technology and the in-home coax tothe video devices. Cable functionalities, such as video, voice andInternet access, may be provided to homes, via coaxial cable, by cableoperators, and use coaxial cables running within the homes to reachindividual cable service consuming devices locating in various roomswithin the home. Typically, home networking over coax typefunctionalities run in parallel with the cable functionalities, ondifferent frequencies.

It would be desirable to achieve maximum power savings with MoCA devicesconnected by a MoCA home network.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and advantages of the subject technology will be apparentupon consideration of the following detailed description, taken inconjunction with the accompanying drawings, in which like referencecharacters refer to like parts throughout, and in which:

FIG. 1 shows a schematic diagram of MoCA Core blocks; and

FIG. 2 shows a schematic diagram of an operational sequence of anexisting MoCA node (“EN”) entering standby state;

FIG. 3 shows a schematic diagram of an operational sequence of an ENre-entering running state;

FIG. 4 shows a schematic diagram of another embodiment of an operationalsequence of a transmission to an EN in standby state;

FIG. 5 shows an exemplary embodiment of a system that may use themethods described herein to reduce power consumption in a MoCA network;

FIG. 6 shows a schematic diagram of the operation of a standby stateaccording to one or more implementations;

FIG. 7 showing a schematic diagram of an operational sequence of astandby node according to one or more implementations;

FIG. 8 shows a schematic diagram of power dependence for a networkdevice in a system according to one or more implementations;

FIG. 9 shows a schematic diagram of a power state transition sequenceaccording to one or more implementations;

FIG. 10 shows a schematic diagram of active standby/idle standby modetransition for a MoCA node participating in a periodic Link MaintenanceOperation (LMO) according to one or more implementations; and

FIG. 11 is a schematic diagram of an illustrative single or multi-chipmodule of the subject technology in a data processing system.

DETAILED DESCRIPTION

In the following description of the various embodiments, reference ismade to the accompanying drawings, which form a part hereof, and inwhich is shown by way of illustration various embodiments in which thesubject technology may be practiced. It is to be understood that otherembodiments may be utilized and structural and functional modificationsmay be made without departing from the scope and spirit of the presentdisclosure.

As will be appreciated by one of skill in the art upon reading thefollowing disclosure, various aspects described herein may be embodiedas a method, a data processing system, or a computer program product.Accordingly, those aspects may take the form of an entirely hardwareembodiment, an entirely software embodiment or an embodiment combiningsoftware and hardware aspects. Furthermore, such aspects may take theform of a computer program product stored by one or morecomputer-readable storage media having computer-readable program code,or instructions, embodied in or on the storage media. Any suitablecomputer readable storage media may be utilized, including hard disks,CD-ROMs, optical storage devices, magnetic storage devices, and/or anycombination thereof.

In addition, various signals representing data or events as describedherein may be transferred between a source and a destination in the formof electromagnetic waves traveling through signal-conducting media suchas metal wires, optical fibers, and/or wireless transmission media(e.g., air and/or space).

The specification describes a method for providing power management. Inone or more implementations, the specification describes a method toachieve a power saving mode of MoCA devices that can work together withthe current MoCA 1.1 specifications and a suitable power-out saving MoCAprotocol. The subject technology may provide a protocol whereby aMoCA-based device may be placed in standby state. The standby state canreduce power consumption of the device while allowing the device to besubstantially instantaneously reactivated either locally—i.e., on thefront panel of the set top box or remote IR—or remotely—i.e., from adifferent networked device within the home. The remote reactivation mayoccur over the MoCA network.

For ease of reference, the following glossary provides definitions forthe various abbreviations and notations used in this patent application:

ARP Address Resolution Protocol

digital PHY Includes port of the MoCA integrated circuit that forms aconduit for signals to and from a receiver and/or transceiver integratedcircuitEN MoCA Existing Node (the term “node” may be referred to alternativelyherein as a “module”)

IE Information Element IPV4 IP Version 4 IPV6 IP Version 6

MAC Media Access Controller—includes logic for MoCA integrated circuitthat schedules opening and closing of the digital PHY as needed fortransmission and/or receiving signals from the receiver and/ortransceiver integrated circuit

MAP Media Access Plan NC MoCA Network Controller NN MoCA New Node PDPower Down PHY Physical Layer of MoCA Network PS Power Saving PU PowerUp RO Reservation Request Opportunity RR Reservation Request Message STBSet Top Box SV Standby Vector WoM Wake on MoCA

Several organizations, among them the EC (European Commission) andEnergy Star organization in the US, provide recommendations to reducetotal energy consumption in homes. Among other devices, STBs, digitalTVs and other video/networking devices are considered in therecommendations.

Networked devices, like networked STBs, should preferably maintain theirnetwork in a “live” state even when in a power saving mode in order toenable waking up of remote nodes. This is commonly referred to as Wakeon LAN. Both Energy Star and the EC provide recommendations fornetworked devices that are in standby state but need to maintain theirnetwork connection ON.

Currently Wake on LAN (WoL) is specified for Ethernet and is beingconsidered for WiFi. As MoCA becomes a prevailing home network platformthat connects consumer electronics devices, a Wake on MoCA feature ismuch desired. While the current MoCA 1.1 specifications lack anydefinition of power saving, it is possible to achieve significant powersaving according to the subject technology while maintaining MoCAnetwork connectivity ON in standby state.

The following overview relates to power saving mode requirements relatedto MoCA, current power consumption of the MoCA core, and systems andtechniques for power saving operating modes that are associated with ECCoC and Energy Star recommended standby states. Techniques according tothe subject technology for power saving comply with MoCA 1.1. Techniquesaccording to the subject technology are applicable to a network wherenodes are configurable in standby states according to the subjecttechnology. Such configurable nodes may coexist with other MoCA 1.1nodes. Such networks, according to the subject technology, may alsoinclude networks comprising only nodes according to the subjecttechnology. Efficient power saving modes according to the subjecttechnology that may operate on top of the current MoCA specifications;and wake on MoCA protocol considerations according to the subjecttechnology are also set forth herein.

A summary of preferable requirements for a MoCA standby state accordingto the subject technology may include the following:

1. Significant power reduction as compared to running—i.e., active,non-standby—state;2. Maintaining network connectivity with remote MoCA nodes in powersaving modes;3. Node in standby state should remain a MoCA “Active” node, as definedlater in the portion of the specification relating to Wake on MoCAimplementations;4. Supporting coexistence of running and standby nodes on a MoCAnetwork;5. Configuring a node to be in standby state when coexisting with otherMoCA manufacturer implementations; and6. Allocating active and idle times to increase power consumptionsavings (as discussed in more detail below in the portion of thespecification corresponding to FIG. 6).

The following section outlines power saving states and theircorresponding power consumption specifications for the MoCA core.

Power Management Specifications

This section summarizes power requirements. See also, MoCA & Powermanagement—by Olivier Harel, which is availablehttp://twiki-01.broadcom.com/bin/view/Chiparch/MoCAPowerManagement,which is incorporated by reference herein in its entirety, for a moredetailed description of EC CoC and Energy Star requirements.

Standby States and Power Targets

The EC recommends two standby states for consumer electronics devicesand their corresponding power goals: 1) Passive standby state—currentlyallows 2 Watts (“W”) Alternating Current (“AC”) per set top box, butplans to reduce power to 1 W AC in the near future (“Aggressive standbystate”). EC CoC does not require network connectivity in passive standbystate but some European countries do require maintaining it. 2) Activestandby state—Requires maintaining network connectivity between thenetworked devices. The power requirement is 3 W AC per set top box.

Energy Star defines a single standby state. Energy Star recommendationsare directed to total annual energy consumption of the box, assumingthat more than 50% of the time it is on standby state. There are nospecific recommendations for the power consumption on standby. However,larger power consumption is allowed for the running mode. Harel assumes3 W AC per box for Energy Star standby state.

Certain assumptions regarding selected power consumption states may beas follows:

European aggressive passive standby at 1 W AC allows 300 mW for the BRCM7420 manufactured by Broadcom Corporation of Irvine, Calif. The onlyconsumption allowed to the MoCA Core consumption is standard cellleakage. The standard cell leakage may be kept low by limiting use of(“LVT”) (Low Voltage Threshold) cells. Preferably all analog componentsshould be powered down (<1 mW) and no activity of any sort isacceptable.

European passive standby state allows 2 W AC, which translates to about1 W DC for a Set-top box.

Energy Star (USA) ES assumes that a set top box would achieve 3 W (AC)in standby; and this translates to just over 1.5 W DC (with OK or othersuitable converters) for the entire set-top box.

MoCA Standby Power Requirements in Harel

The allowed overall BRCM 7420 standby power consumption and the impliedallowed power consumption for a MoCA chip (when working together withthe BRCM 3450, manufactured by Broadcom Corporation of Irvine, Calif.,the companion LNA/PA RF (Low Noise Amplifier/Power Amplifier) (RadioFrequency transmission chip)), are depicted in Table 1 below.

The analysis set forth in Table 1 assumes that apart from MoCA, refreshDDR (Double Data Rate) and the Ethernet subsystem interfacing with theMoCA core are ON, the latter consuming between 500 to 600 mW. In thestandby state set forth in Table 1, MoCA is linked up to the Ethernetsubsystem but is mostly in idle mode. Some embodiments of the subjecttechnology may include reducing the power consumption of the Ethernetsubsystem by awakening it only in response to an interrupt signalgenerated by the MoCA core applying the filtering according to thesubject technology, described in more detail below.

TABLE 1 RF Block Power Consumption Recommended 7420 inc. MoCA core +Power State AC target (W) MoCA (W) 3450 (mW) Active standby 3 1.5800-900 Passive standby 2 1 300-400 Aggressive passive 1 0.3 Onlyleakage standby (EC CoC)

Table 2 shows MoCA Network Status Standby configurations according tothe subject technology.

In standby state, active mode, the MoCA network should typically stay ONalthough no data are transmitted—but the link should be maintained. Inidle standby mode, keeping the network ON is not mandatory but it isdesirable. In aggressive idle mode, the network is OFF and the MoCA coreis powered down.

Typically, the MoCA node is toggled between running state and standbystate in response to a signal external to the node. The MoCA node istoggled between different standby modes in response to a trigger signalinternal to the node.

TABLE 2 MoCA Network Status in Power States Standby Power State MoCANetwork Active mode Link up, no transmit data - Required Passive modeLink up, no transmit data - Preferable Aggressive passive mode (EC Linkdown, MoCA is powered down CoC) (also referred to herein, in thealternative, as powered-down)

In some embodiments, wake up time (time to resume datatransmission/reception operation from MoCA standby state in idle mode)should preferably be kept under 20 milliseconds and most preferablyunder about 10 milliseconds.

Required wakeup time from power down is typically longer than wake uptime from standby state. Wakeup time from power down typically requiresthe node to be re-admitted to the network. Assuming no channel search isrequired, the readmission should not take longer than 2 seconds.

As only leakage power is allowed on aggressive passive standby,rebooting the MoCA core may be required. Rebooting typically adds 75milliseconds to the power-up time.

MoCA Core Power Consumption

This section relates to power consumption of the main power consumingblocks of the MoCA core. Overall power consumption reduction accordingto the subject technology in several operating modes is analyzed.

The section illustrates the amount of power saving that can be obtainedby improving power consumption and (Power Up/Power Down) “PU/PD” timesof the various blocks.

FIG. 1 shows a schematic diagram of circuitry blocks that consume powerin a MoCA integrated circuit (“chip”). The circuit shown in FIG. 1 mayor may not be integrated with another integrated circuit. Block 102shows that an exemplary Broadcom 3450 chip, manufactured by BroadcomCorporation of Irvine, Calif. may be used in conjunction with the MoCAintegrated circuit described herein. In some embodiments, the Broadcom3450 chip may receive a clock signal and/or receive a power control linesignal for powering down. Block 104 shows transmitting a localoscillator signal from a direct digital frequency synthesizer 120.Direct digital frequency synthesizer 120 receives a MoCA REF PLL 118(MoCA Reference Phase Lock Loop Signal) from an external clock signalgenerator 116.

External clock signal generator 116 also provides a clock signal to MoCACore 122 that preferably runs continuously as it generates the MoCAnetwork clock.

MoCA Core 122 provides a PHY sysclk (system clock) to the digital PHY110 (Physical Layer of the MoCA device), a network clock to System/MAC112 and a SYS clk to the CPU 114 (which is the processor for the MoCAcore.) CPU 114 may be implemented as a MIPS or other suitable processor.

MoCA Core 122 may also provide a signal to USDS_PLL (PHY_PLL) 124 (thePHY phase lock loop) which, in turn, may provide clock signals to ananalog-to-digital converter circuit 126 and a digital-to-analogconverter circuit 128. While legacy MoCA specifications did not allowanalog-to-digital converter circuit 126 and digital-to-analog convertercircuit 128 to toggle because of shut-down times, shortened ADC/DACpower up/power down times in MoCA 2.0 preferably allows for the togglingof analog-to-digital converter circuit 126 and digital-to-analogconverter circuit 128 in order to save power, as necessary.

In certain embodiments according to the subject technology, in order tosave power but maintain the MoCA module connected to the network, thenetwork clock generated by chip 122 and a network timer located insystem/MAC 112 may be maintained in an ON state. However, the gatedclock to digital PHY 110 and the gated clock to System/MAC 112 may beselectively turned OFF, which, in turn, powers down digital PHY 110 andSystem/MAC 112. Accordingly, substantial power may be saved by onlyselectively providing the network clock to digital PHY 110 and toSystem/MAC 112.

The network timer (typically programmed by software) provides a signalto CPU 114. The timer receives the network clock signal from chip 122.When the timer expires, the timer can reactivate CPU 114 by waking upthe CPU 114 with an interrupt signal.

Preferably, because MoCA is a coordinated network, the timing of futureevents is deterministic—i.e., the timing of at least one MAP cycle intothe future and at least one Beacon (ten MAP cycles) into the future maybe known. Therefore, different blocks can be activated ahead of time sothat they can be ready to transmit at known points in time.

For example, if a MoCA core is aware that it will receive a transmissionat time t, it can reactivate the necessary blocks at time t minus delta,where the delta is the time needed to resynchronize to the networkclock.

Table 3 depicts the RF power consumption of a selection of the blocksshown in FIG. 1 according to the subject technology in various modes.

TABLE 3 RF Block Power Consumption RF LO REF PLL 3450 Power (mW) TX mode420 300 120 1000 RX mode 450 300 120 600 Power Down mode <1 <1 <1 <1Timing (microseconds) Power Up 0.5 40 4 0.5 Power Down 0.5 40 4 0.5

Switching times of LO and PLL in Table 3 assume that the PLL has alreadybeen synchronized; otherwise PLL acquisition typically adds another 1millisecond.

In running state, power consumption of transmission/receiving (“TX/RX”)depends on the actual data transmissions. When no data is transmitted orreceived, the RF parts can preferably be maintained in Power Down mode.However, due to the long LO switching times, PLL/LO should be kept ONduring normal operations.

In standby state, switch transmission/receptions are adapted forintervals that are preferably long enough to enable the LO/PLL to bepowered down.

Table 4 depicts the Analog-to-Digital Converter/Digital-to-AnalogConverter (“ADC/DAC”) power estimations in various modes.

TABLE 4 Converters Block Power Consumption USDS PLL [NEED Power m(W) RX(ADC) TX (DAC) DEFINITION] TX mode 226 153 120 RX mode 426 <1 120Power-down mode 0.7 <1 TBD Timing (microseconds) RX (ADC) TX (DAC) USDSPLL Power Up 0.5 (from standby) .05 40 1000 (from PD) Power DownApplication .05 40 Dependent

In certain embodiments, setting the ADC and/or the DAC in Power Downmode may be prevented by their relatively long Power Up time. In otherembodiments, when the ADC/DAC has relatively shortened (toggle) powertransition time, the ADC and/or DAC may be toggled to save power.

Table 5 depicts the ADC digital power estimations in various modes

TABLE 5 MoCA digital Block Power Consumption CPU System/MAC PHY Powerm(W) Normal Mode 100 400 400 Clock Only 50 200 200 Clock Gated 10 10 10Timing (microseconds) Power Up <1 <1 <1

In running state, MoCA logic is active. In a clock only node—logic isnot active but clock is not gated. In a gated clock node—powerconsumption is mainly due to leakage power. To estimate the CPU powerconsumption in gated clock mode, it is assumed that the CPU enters aWAIT state when the node is idle. The gated clock may preferably beimplemented for the PHY and the System/MAC blocks. It is assumed thatduring a standby state according to the subject technology, even inactive mode, PHY and MAC will not be active so their clocks can begated. The CPU may exit its WAIT state in response to receiving a timerinterrupt.

MoCA Core Estimated Power Consumption in Normal Operation

Table 6 depicts the estimated power consumption for an existing MoCAnode (EN) for two cases:

1) When no data are transmitted: When a MoCA node is in standby state,in idle mode (neither transmitting nor receiving), its expected powerconsumption is about 1.4 W, and could be reduced to about 1.0 W if agated clock is applied according to the subject technology.2) Maximal traffic load: MoCA is expected to consume an average 2.7 W.

TABLE 6 MoCA node power consumption no gated clocks with gated clkwithout and reduced ADC gated clk with gated clk current on idle EN FullEN Full EN Full Power EN No Traffic EN No Traffic EN No Traffic (mW) TXData Load Data Load Data Load RF 614 1532 614 1532 614 1532 ADC/ 236 283236 283 45 261 DAC Digital 462 760 142 722 142 722 MIPS 58 95 24 91 2491 Total 1370 2670 1016 2628 825 2605

The estimated power consumption is based on the following assumptions: asingle MAP and a single control message are transmitted per MAP cycle;five RR messages are transmitted per MAP cycle (worst case); MAP cycleis 1 millisecond long; MAP, RR and Control non-data frames (MOCA networkcontrol frames) LMO, SEC, PROBE, KEY (security) all are about 52microseconds long; when active, a node is transmitting and receiving 50%of the time; when idle, RF is powered down and clock is gated whereverit is applicable; and, in full MoCA traffic load, the node is active 90%of the time.

The MoCA 1.1 protocol allows significant power reduction when thenetwork is ON but no data is transmitted over the network. In methodsaccording to the subject technology, the Network Controller (NC) couldincrease the MAP cycle duration up to 2.5 ms, while allowing a singleReservation Request opportunity per MAP cycle. In one embodiment,preferably all nodes would be required to either receive or transmitduring less than 10% of the time, while for the other 90% of the time,the RF/ADC and PHY blocks would be idle.

Power Saving Schemes According to the Subject Technology (MoCA 1.1Compliant)

In this section, power consumption of a MoCA EN is estimated when it isin a standby state. Three levels of power saving modes are identified,according to the subject technology. Implementation of the modes maydepend on interoperability requirements:

1. A MoCA 1.1 network where the NC is not a node according to thesubject technology

In this mode the MoCA Core acts as a node in the running state with nodata to transmit or receive. The core can be on its PHY/RF idle modeabout 85% of the time. When idle, the clock is gated and RF is powereddown. PLLs and ADC cannot be powered down due to longer power up times.

In such a mode, the MAP cycle is assumed to be about 1 millisecond onaverage.

2. A MoCA network where the NC is a node according to the subjecttechnology—in one embodiment that may be configurable in standby statesaccording to the subject technology—but ENs can be either nodesaccording to the subject technology or other conventional nodes

In this mode the NC can adapt the MAP cycle to network activity byincreasing MAP cycle duration (up to 2.5 milliseconds allowed by theMoCA specifications) and lowering the periodicity of the ROs to a singleRO per MAP CYCLE for nodes according to the subject technology that arein standby state (can be even lower when only nodes according to thesubject technology are on the network). When the NC discovers activityon the network it can return to level 1.

In this mode, when no data is transmitted over the network, ENs couldleave idle mode once in 2.5 milliseconds, PLLs and RFs are powered downin addition to gating the clock. The ADC cannot be powered down exceptwhen its power up time has improved significantly.

This mode is preferably fully compliant with the MoCA 1.1 and caninteroperate with conventional nodes. However, when conventional nodesare admitted on the network, the NC according to the subject technologymay require more power to support them.

3. A MoCA 1.1 protocol where the NC and all nodes are nodes according tothe subject technology

In one embodiment of the subject technology, this mode enables the nodesaccording to the subject technology to be awakened only once in apredetermined time—e.g., 10 milliseconds—to further reduce powerconsumption. Both PLLs and ADC may preferably be powered down in thismode. A message passing method according to the subject technology,preferably compliant with MoCA 1.1 specification may be applied (seedescription below for more detail).

Thus, power saving can be improved by switching the RF/ADC/PHY/MACblocks efficiently between running and standby states, and bysignificantly reducing power consumption of these blocks when in standbystate.

Table 7 depicts estimated power consumption on each of the power savingmodes, wherein “proprietary” denotes a node that may be configuredaccording to the standby state and modes set forth in Table 2:

TABLE 7 EN Power Savings Modes Power Consumption (mW) Current w/gatedw/improved Mode NC ENs design clock ADC PD 1 Non- Proprietary & 13701000 850 Proprietary Non-Proprietary 2 Proprietary Proprietary & 1210420 210 Non-Proprietary 3 Proprietary Proprietary only 1120 80 80

To simplify the discussion of the integration of the MoCA power saving,this application defines below in Table 8 four MoCA Core Power Savingstates M0 to M3 that correspond to the open Advanced Configuration &Power Interface (“ACPI”) specifications [4] [www.acpi.info], which ishereby incorporated by reference herein in its entirety.

TABLE 8 Suitable MoCA Core to receive Power Wakeup State DescriptionsInterrupt M0 - MoCA Core is running. No Running Full networkcapabilities. Analog parts could be powered up/down on schedule. 3M1 -MoCA Core timers only are always on. Yes Standby The other blocks of theMoCA Core wake up on timer interrupts to handle MoCA Control trafficonly (e.g., Beacons, MAPS and RRs), to keep the MoCA Core “virtually”connected. MoCA Core filters ingress MoCA frames and asserts a Wake-upinterrupt for Wake-up frames. Maximum power saving if the NC node is aBroadcom node. Minimum power saving if the node is not a Broadcom node.M3 - MoCA core is powered down. No network No Down connection. Fullreboot is required to reenter the running state.

Table 9 below sets forth the possible transitions from Power Savingmodes and their associated commands:

TABLE 9 From M1 Standby M3 Power To M0 Running State (Active or Idle)Down M0 Host Request Host Reboot M1 Host Request — M3 Host Request —

This section details the embodiment for power saving techniques,according to the subject technology, in the case where the entire MoCAnetwork includes nodes according to the subject technology. This mode ispreferably MoCA 1.1 compliant; however, it may rely on proprietarymessaging that runs over the MoCA 1.1 protocol.

FIG. 2 shows a schematic diagram of an operational sequence of an ENentering standby state.

Step 201 shows the EN sending a request to the NC to enter standby stateby asserting the bit associated with its node_ID into the Standby Vector(SV) Information Element of its Null (i.e. no transmission opportunityis requested) Reservation Request Frame.

Step 202 shows the NC acknowledging the EN's standby transition requestby asserting the bit associated with the node_ID of the requester ENinto the Standby Vector (SV) Information Element of the MAP frame. Thisis shown by the ACK message along the curved, hatched line that isadjacent the running NC line.

The NC preferably reduces the periodicity of the scheduled ROs for thesuspended node to one RO per Beacon period.

Step 203 shows that, in the last MAP frame before the Beacon, the NCasserts in the Next MAP Vector (NV) Information Element all the bitsassociated with standby nodes. This assertion indicates to the runningnodes that a transmission request to a standby node can be made in thenext scheduled Request Opportunities. These transmissions can be madebecause Standby Nodes will preferably receive and parse the MAP frame inthe next MAP cycle. The EN toggles to active mode on the next scheduledBeacon to get the scheduled time of the next MAP frame and re-enters itsidle mode. Thereafter, Step 204 shows the standby node receiving theBeacon. The Beacon indicates where the first MAP will be. The standbynode can receive the 1st MAP frame (Step 205) scheduled by the beaconand can parse the MAP frame.

The repeat of steps 203 and 204 shows that, if the EN misses the MAPframe, it can retry on the next Beacon cycle.

Step 206 shows that the EN may send an RR (in MoCA 2.0) after the 1^(st)MAP after the Beacon even if it has no pending frame to transmit.

In step 205, the MAP parsing generates two possible scenarios: If thebit associated with the next MAP Vector (NV) is asserted, the standbynode should receive the next MAP (step 207). This scenario can repeatitself until the bit associated with the Next MAP Vector (NV) isde-asserted (step 208). Once the bit associated with the next MAP Vector(NV) is de-asserted, the standby node re-enters idle mode until the nextscheduled Beacon (step 204) and ignore any remaining subsequent MAPswithin the current Beacon period (steps 209). The curved, hatched linesalong the left side of the Node S line indicate the various points atwhich the standby node has been instructed to be in active standby mode.

FIG. 3 shows a schematic diagram of an operational sequence of an ENre-entering running state. When the system elects to send a packet overthe MoCA network, the system may indicate to the MoCA Node a Standby(M1) to Running (M0) State transition.

The following description corresponds to the exemplary steps shown inFIG. 3. Step 301 shows the EN getting an M1 standing to M0 runningrequest from an external source (the upper layer of the host entity),i.e., the system on which the node is located.

Step 302 shows the EN sending a request to the NC that the node tore-enter Running State by de-asserting the bit associated with itsnode_ID into the Standby Vector (SV) Information Element of itsReservation Request Frame.

Step 303 shows the NC acknowledges the EN's transition by de-assertingthe bit associated with the node_ID of the requester EN into the StandbyVector (SV) Information Element of the MAP frame.

FIG. 4 shows a schematic diagram of another embodiment of an EN/NC thatwants to transfer a frame to EN(s) in standby state, as shown in step401. The following description corresponds to the exemplary steps shownin FIG. 4.

The running EN/NC is typically aware: a) which destination nodes are inStandby State (from the Standby Node Vector (SV) in MAP Frames), and b)the nature of the 802.3 frame to be transmitted—e.g., Unicast (singlenode recipient), Multicast (plurality of preferably selected recipients)or Broadcast (send to all nodes).

Step 402 shows that, for a MAC Unicast and/or a MAC Broadcast frame, therequesting EN(s) await(s) the assertion of the bit associated with thedestination node ID in the Next MAP Vector (NV) in the MAP frame to senda Reservation Request for the pending transmission in its next scheduledRR 403.

For MAC Multicast frame, the EN can ignore standby nodes, as standbynodes are typically not members of any Multicast groups. Generally, inmethods according to the subject technology, nodes de-register from anyMulticast group upon transitioning to standby state.

Step 404 shows that the NC can grant the RRs in the MAP following theBeacon. If the NC cannot grant a request in the next MAP cycle, the NCmay grant a request in the subsequent MAP cycle(s) by indicating to anode to receive the subsequent MAP frame(s). In one embodiment of thesubject technology, the NC may provide an indication by keeping the bitassociated with the destination node ID asserted in the Next MAP Vector(NV) in the MAP frame.

Step 405 shows the transmission to the node in standby node. The Standbynode can toggle to active/idle modes within standby to receive anyscheduled event and toggle to idle mode before scheduled events. TheBeacon indicates when the MAP frame is scheduled. The standby nodes canthen receive the MAP frame and parse it.

If more transmissions are pending, the NC may schedule transmissions inthe MAP cycles subsequent to the first MAP following the Beacontransmission by keeping the bit associated with the recipient standbynodes asserted in the Next MAP Vector (NV) of the MAP frames.

Certain aspects of the subject technology relate to transmit and NC MoCANode handling in a mixed MOCA network of nodes in Standby and Runningstates.

A running node can transmit 3 types of MAC frames: Unicast, Multicast,and Broadcast.

It should be noted that the extraction of the MAC address type of theIEEE 802.3 ingress frames is supported by the device hardware andsoftware readable to the requester

The table below lists all possible transmission cases and one embodimentaccording to the subject technology of their respective TX and NChandling.

TABLE 10 Transmission Possibilities Type Handling Unicast MAC UnicastNormal Tx Broadcast MAC Broadcast Delayed Rx: (wait for Standby nodes tobe active) Wait for IE NM = 1 in MAP before requesting RR for TxMulticast/ MAC Multicast Ignore Standby Nodes Broadcast (MoCA (NoMulticast Members on Broadcast) Standby Nodes) Normal Tx

Another aspect of the subject technology relates to an NC enteringStandby State. An NC that is entering standby state should preferablyinitiate an NC handoff with one of the running ENs of the network. Ifthe NC is the last running node of the network, it could enter itsstandby state and:

(1) extend its MAP cycle to send only one (or two to compensate time)MAP per beacon period (of every 10 ms, nominal, or of other suitableduration); and/or(2) whenever a node on the network indicates that it re-entered itsRunning State, the NC can also re-enter its Running State.

Yet another aspect of the subject technology relates to a systemreferred to herein as “Wakeup on MoCA (‘WoM’).”

Table 11 describes the WoM pattern filtering of a MoCA node.

TABLE 11 Wake on MOCA Frame Filtering Patterns Frame type WoM filteringpattern MAC address IPV4 ARP Broadcast MAC DA + ARP ETH TYPE resolution(Broadcast) (0x0806){(+TARGET PROTOCOL ADDRESS)} IPV6 Neighbor MULTICASTMAC DA BIT + Discovery IPV6 ETH TYPE (0X86DD) + PROTOCOL IPV6 HEADERPARSING TO 1PV6 MESSAGES(Multicast) ICMP HEADER + NEIGHBOR ICMP TYPE[133 . . . 137] SOLICITATION {(+TARGET PROTOCOL ADDRESS)} ROUTERSOLICITATION ROUTER ADVERTISEMENT REDIRECT MSG MULTICAST Directed FrameUnicast MAC DA bit Magic Packet ™ Broadcast MAC DA (destinationaddress) + 0xFFFFFFFFFFFf

The MAC Address Resolution preferably provides translation of an IPaddress to a MAC address. Using IPV6, the Multicast MAC DA (DestinationAddress) allows the node to be virtually connected even though the nodeis in standby state. This protocol may be implemented by signaling thereception of a few specific network protocol frames to a system instandby state. Such signaling allows the system to wake up and answerthese frames, thereby preventing their respective network or transportprotocols from timing out. Such IP specific frames may include 802.3Unicast frames, IPv4 ARP frames, and/or IPV6 IGMPv6 Network DiscoveryNeighbor/Router Solicitation and Update Message frames. Such atechnique, according to the subject technology, preferably precludes theneed for a power management proxy and/or a special protocol.

FIG. 5 shows an exemplary embodiment of a system that may use themethods described herein to reduce power consumption in a MoCA network.FIG. 5 preferably includes a first TV display 502, a set top box 504, asecond TV display 506 and second set top box 508. First set top box 504and second set top box 506 may be connected by a coax network 510.

First set top box 504 includes a local storage 512. Such local storagemay store movies on a hard disk or other suitable storage medium. Eachof set top boxes 504 and 508 (or just first set top box 504) may becapable of a soft OFF which would place the set top box in a standbystate according to the subject technology. A soft OFF button may bemounted on the front panel of the set top box or the IR remote.

In one embodiment of the subject technology, first set top box 504 maybe in standby state. In this embodiment, second set top box 508 canaccess the hard drive on first set top box 504, for example, to play themovie stored on hard disk 512 of first set top box 504 on second TVdisplay 506—even though first set top box 504 is in standby state.

FIG. 6 shows a schematic diagram of the operation of a standby stateaccording to one or more implementations of the subject technology. FIG.6 shows that a standby node 602 according to the subject technology maybe characterized such that the set top box stays active by listening tobeacons 604 and the first MAP 606 following a Beacon. The relative timeof the next MAP may be indicated in the beacons which are sent by theNetwork Controller in absolute time.

The rules, according to the subject technology, associated with astandby node may be as follows. The standby node may always be listed ina predetermined MAP—e.g., the first MAP frame after a beacon—andcontinue to listen to subsequent MAPs, as shown at 608, as the NV vectorin the MAP frames indicate. When the NV vector indicates otherwise, thestandby node 602 may not listen to MAPs in the current beacon period, orother predetermined beacon period, until the first MAP of the nextbeacon period.

FIG. 7 shows another schematic diagram of an operation of a node instandby state according to one or more implementations of the subjecttechnology. In FIG. 7, following the first beacon 701, the standby nodelistens to only the first MAP 702 of the beacon period. Thereafter, thestandby node returns to idle mode in response to the deasserted bit inthe NM vector.

Following the second beacon 701, the standby node listens to the firstMAP 703 and the second MAP 704 in response to the asserted bit in the NMvector of the first MAP 703 of the second beacon period. Thereafter, thestandby node returns to idle mode in response to the deasserted bit inthe NM vector of the second MAP 704.

Beacon 705 is shown as well. It should be noted that every MAP beforethe beacon typically has the bit in the NM vector asserted in order tocause the standby node to listen to the first MAP following the vector.

The foregoing analysis assumes that, apart from MoCA, refresh DDR andthe Ethernet subsystem interfacing the MoCA core are ON, the latterconsuming between 500 to 600 mW. MoCA is linked up but is mostly idle.Other embodiments of the subject technology reduce the power consumptionof the Ethernet subsystem by waking it in response to an interruptgenerated by the MoCA core applying the filtering described above.

Preferably, the subject technology could provide for remote access overthe network while in standby state without any sideband method orprotocol other than TCP/IP. Systems and methods according to the subjecttechnology may adapt MoCA-based products to be Energy Star and ECCompliant, may provide for remote management capabilities of MoCA-basedproducts while the products are in standby state, and may provide theproducts with substantially instantaneous return to full functional modefrom standby state.

In the MoCA 1.1 specification, a non-active node to the network iseither left fully active even in case of no activity or shut down tosave energy. Re-entering the network requires the full admission processwhich lasts several seconds.

Several organizations, among them the EC (European Commission) andEnergy Star organization in the US, are writing recommendations toreduce total energy consumptions in homes. Among others, STBs, digitalTVs and other Video/networking devices are considered. In particular,they include recommendations for power efficient standby states forSTBs, as these devices are expected to be in a non operating state mostof the time.

Networked devices, like networked STBs, should desirably maintain theirnetwork alive even when in a power saving mode, to enable waking upremote nodes. Both Energy Star and the EC provide recommendations fornetworked devices that are in Standby state but need to maintain theirnetwork on.

FIG. 8 shows a schematic diagram of power dependence for a networkdevice in a system according to one or more implementations of thesubject technology. Specifically, FIG. 8 shows the coupling of a memorymodule 802, a bus 804, a conventional NIC (Network Interface Controller)806 and a MoCA NIC 808 according to the subject technology. In order forthe NICs 806 and/or 808 to function, the NICs need to be able to saveinto memory module 802 and pull from memory module 802. In addition, bus804 should be powered in order to facilitate communication between NICs806 and/or 808 and memory 802.

When a NIC transitions to a running state, it typically immediatelybegins transmitting data. Therefore, in order to transition from astandby state to a running state, memory 802 and bus 804 must first bepowered up prior to the powering up of NICs 806 and/or 808.

Step 902 shows an M1 Power State request directed from a host to theMoCA adapter of the MoCA node 902. Thereafter, the WoM filtering isimplemented to determine whether a wakeup signal from the host internalcontrol is included in the Power State Request, as shown at step 904.The wakeup signal is used to indicate to the system the reception of aframe of interest for the system (a frame upper layer network protocolshould handle and answer to prevent protocol time out). As a result ofthe wakeup signal, the system may first power the system modules neededto receive the frame retained by the MoCA device (such powering thememory, then the data bus connected to the MoCA device in order totransition from B1 to B0 state), as shown as 906 and 908. At step 910,upon completion of this sequence (based on the exemplary powerdependency described in FIG. 8.), the MoCA device may be requested tore-enter from M1 to M0 power state. At step 912, the MoCA device hasre-entered M0 state and could deliver the received frame to the systemmemory for handling by the higher layer entities.

Yet another aspect of the subject technology relates to Power ManagementMessages. Power Management MoCA Management Protocol (“MMP”) messagesaccording to the subject technology may be sent by the host to requestthe MoCA Node to transition from one Power Mode State to another. Suchmessages may include the following:

Running State (M0) to Sleeping State (M1);

Running State (M0) to Down State (M3); and

Sleeping State (M1) to Running State (M0).

The MoCA Core response to the transition request indicates the status ofthe transition. If the transition was successful within the MoCAprocessing core—i.e., the processing module associated with MoCAfunctions—the response returns a success status. Otherwise, the responsecan return a rejection status and the reason for the rejection.

A MoCA Wakeup frame from a host system may trigger a transition requestat the MoCA core from Standby State (M1) to Running State (M0).

FIG. 10 shows a schematic diagram of active standby/idle standby modetransition for a MoCA node participating in a periodic Link MaintenanceOperation (“LMO”) according to the subject technology. Lines 1002, 1004show the transitioning of a node in standby state as it participates inan LMO. Time line 1006 shows that, when another node has assumed theposition of LMO node, the standby node only has to be in active mode fordurations 1010 and 1012. It should be noted that during duration 1010,which is expanded in greater detail at 1008, standby node only has to beactive for the probe periods and to provide a probe report. Putting thestandby node in idle state during the latency periods can provide addedpower savings. The time between each probe is typically 20-350milliseconds plus a latency of about 10 milliseconds (for beaconsynchronization). Finally, the standby node should remain active duringLMO GCD (the determination of Greatest Common Density period), in whichscheduling the active/idle time of the standby node becomes too complex.

When the M1 node assumes the position of LMO node, then the LMO stays inactive mode for the entire LMO process (toggling to idle mode mayproduce insignificant power saving in regard to the active/idle moderatio during LMO node sequence).

The distance between each probe is typically 20-350 milliseconds+alatency of about 10 milliseconds (for beacon synchronization).

In certain embodiments of the subject technology, an NC can select an M1Node to be the LMO node at reduced periodicity. For example, in anetwork of only two nodes, the NC can select an M1 Node at the sameperiodicity that exists in a full 16 node network. The Period for theLMO=(16*LMO sequence (˜0.5 sec per node)+T6 (1 sec))=9 sec. When the M1node is selected as the LMO Node, the M1 node can stay ON for the wholeLMO sequence. When the M1 node is selected as an “Other Node”, the M1node can fully participate in the LMO in ON/IDLE mode to minimize powerconsumption. Such limited selection of the M1 node can preferably savepower consumption.

Yet another aspect of the subject technology relates to Power ManagementProtocol Information Elements. The Standby Vector (SV) ProtocolInformation Element can be added to:

1. a Reservation Request frame by an EN as a request to transition to astandby state or a request to transition to a running state. Thisrequest may be initiated by the host requesting the node to transitionfrom Running State (M0) to Standby State (M1) or vice-versa from standbystate (M1) to running state (M0). In order to trigger such a request,the node can assert the bit associated with its node ID in the StandbyVector.

2. a MAP frame by the NC to indicate to all the nodes of the MoCAnetwork the Power State of each node. An asserted bit in the StandbyVector indicates that the node with the associated node_ID is in StandbyState. A de-asserted bit indicates that the node with the associatednode_ID is in Running State.

The Next MAP Vector (NV) Protocol Information Element can be added to: aMAP frame by the NC to indicate:

1. to all the running nodes of the MoCA network if reservation requeststo transmit to standby nodes could be made in the next scheduled RRs. Anasserted bit in the Next MAP Vector indicates that reservation totransmit to the node with the associated node_ID could be made in thenext scheduled RR. A de-asserted bit indicates that reservation totransmit to the node with the associated node_ID could not be made.

2. to selected standby nodes that they should reactivate themselves intime to receive the next scheduled MAP frame. An asserted bit in theStandby Vector indicates that the node with the associated node_IDshould receive the next MAP frame. A de-asserted bit indicates that thenode with the associated node_ID that no more MAP frames should bereceived within the current Beacon Period.

Table 12 sets forth an embodiment of the Standby Vector ProtocolInformation Element and Next MAP Vector Protocol according to thesubject technology.

TABLE 12 Standby Vector Protocol Information Element Field Length UsageProtocol IE Header 4 bits Pre-determined value to determine which frametype 4 bits Pre-determined value to determine which frame type 6 bits 12 bits Type III Protocol IE Payload 16 bits Bitmask. Each bit of thebitmask is associated with a node ID - LSB is node 0. Bit_i = 1: in MAP:Node_i is in standby state in RR: transition to standby state requestBit_i = 0: in MAP: Node_i is in running state in RR: transition torunning state request 16 bits For Running State: Indicates sending an RRin the next MAP cycle For Standby: Indicates where to stay awake for thenext MAP Bitmask. Each bit of the bitmask is associated with a node_ID -LSB is node 0. This Vector is meaningful only for the nodes set inStandby Node Vector Bit_i = 1: Indicates that RR allocated to Node i maybe requested in the next MAP cycle Bit_i = 0: Indicates that RRallocated to Node i should not be requested in the next MAP cycle

Network Management for Node in Standby State

Link Management Operation (LMO)

The NC should reduce the frequency in which it selects a node in StandbyState NC to be the “LMO node.” The LMN node is typically used todetermine GCD (Greatest Common Density period). Link management protocolin general may be used to maintain control channel connectivity, verifythe physical connectivity of the data links, correlate the link propertyinformation, suppress downstream alarms, and localize link failures forprotection/restoration purposes in multiple kinds of networks.

The node in standby state, according to the subject technology, canparticipate as a node in running state in all the MoCA NetworkManagement Protocol (LMO, topology update, privacy, etc.). There is adifference within standby state. A node in standby state is not requiredto be selected as an LMO node (master or the LMO) at the same frequencyas a node in running state. Rather, a node in standby state can stay inactive mode during the whole interval that it is the selected LMO nodeand can toggle between active and idle mode when it is a slave to“another” LMO mode. The details of the operation of an LMO nodeaccording to the subject technology are shown below in the portion ofthe specification corresponding to FIG. 10.

FIG. 11 shows a single or multi-chip module 1102 according to thesubject technology, which can be one or more integrated circuits, in anillustrative data processing system 1100 according to the subjecttechnology. Data processing system 1100 may include one or more of thefollowing components: I/O circuitry 1104, peripheral devices 1106, aprocessor 1108 and memory 1110. These components are coupled together bya system bus or other interconnections 1112 and are populated on acircuit board 1120 which is contained in an end-user system 1130. System1100 may be configured for use in a cable television tuner according tothe subject technology. It should be noted that system 1100 is onlyexemplary, and that the true scope and spirit of the subject technologyshould be indicated by the following claims.

Thus, systems and methods for providing a MoCA power management strategyhave been described.

Aspects of the subject technology have been described in terms ofillustrative embodiments thereof. A person having ordinary skill in theart will appreciate that numerous additional embodiments, modifications,and variations may exist that remain within the scope and spirit of theappended claims. For example, one of ordinary skill in the art willappreciate that the steps illustrated in the figures may be performed inother than the recited order and that one or more steps illustrated maybe optional. The methods and systems of the above-referenced embodimentsmay also include other additional elements, steps, computer-executableinstructions, or computer-readable data structures. In this regard,other embodiments are disclosed herein as well that can be partially orwholly implemented on a computer-readable medium, for example, bystoring computer-executable instructions or modules or by utilizingcomputer-readable data structures.

What is claimed is:
 1. A network device, comprising: one or morememories; and one or more processor circuits coupled to the one or morememories, the one or more processor circuits configured to cause:providing for transmission a request directed to a network controller tochange a power state of the network device, wherein the network deviceis configurable to change the power state between a running power stateand a standby power state, the standby power state comprising an activemode and an idle mode; receiving a grant from the network controller inresponse to the request, and changing the power state of the networkdevice in response to receiving the grant, wherein: the running powerstate is associated with higher power consumption than the active modeand the idle mode; the active mode is associated with higher powerconsumption than the idle mode; in the active mode, the network deviceis configured to receive at least one Media Access Plan (MAP); and inthe idle mode, the network device is configured to ignore MAPs.
 2. Thenetwork device of claim 1, wherein the one or more processor circuitsare configured to cause embedding the request in a reservation requestand providing for transmission the reservation request.
 3. The networkdevice of claim 1, wherein the one or more processor circuits areconfigured to cause receiving a MAP, the MAP comprising the grant. 4.The network device of claim 1, wherein the one or more processorcircuits are configured to cause: receiving a beacon signal; andtransitioning the network device from the idle mode to the running powerstate in response to receiving the beacon signal.
 5. The network deviceof claim 1, wherein the one or more processor circuits are configured tocause: receiving a beacon signal; and transitioning the network devicefrom the active mode to the running power state in response to receivingthe beacon signal.
 6. The network device of claim 1, wherein, in theidle mode, the network device is configured to maintain a link to anetwork.
 7. The network device of claim 1, wherein, in the active modeand the idle mode, the network device is configured to receive a beaconsignal.
 8. The network device of claim 1, wherein, in the active mode,the network device is configured to participate in a link maintenanceoperation (LMO).
 9. A tangible computer-readable storage medium storingcomputer-executable instructions that, when executed by one or moreprocessors, cause one or more processors to perform operations, theoperations comprising: receiving a request for changing a power state ofat least one network device between a running power state and a standbypower state, wherein the standby power state comprises an active modeand an idle mode; and providing for transmission a response to therequest to change the power state of power state of the at least onenetwork device, wherein: the running power state is associated withhigher power consumption than the active mode and the idle mode; theactive mode is associated with higher power consumption than the idlemode; in the active mode, each of the at least one network device isconfigured to receive at least one Media Access Plan (MAP); and in theidle mode, each of the at least one network device is configured toignore MAPs.
 10. The tangible computer-readable storage medium of claim9, wherein the receiving the request comprises receiving a reservationrequest with the request for changing the power state embedded in thereservation request.
 11. The tangible computer-readable storage mediumof claim 9, wherein the operations further comprise embedding, in theresponse, a grant to the request to change the power state of the atleast one network device.
 12. The tangible computer-readable storagemedium of claim 11, wherein the response comprises a MAP.
 13. Thetangible computer-readable storage medium of claim 9, wherein theoperations further comprise providing for transmission a beacon signaldirected to the at least one network device.
 14. A computer-implementedmethod, comprising: configuring a power state of a network device to bein a running power state; providing for transmission a request directedto a network controller to transition the power state of the networkdevice from the running power state to a second power state, wherein:the second power state is one of an active mode or an idle mode, therunning power state is associated with higher power consumption than theactive mode and the idle mode, and the active mode is associated withhigher power consumption than the idle mode; receiving a signal from thenetwork controller in response to the request; and transitioning thenetwork device from the running power state to the second power statebased on the signal, wherein: when in the active mode, the networkdevice receives at least one Media Access Plan (MAP), and when in theidle mode, the network device is not able to receive MAPs.
 15. Thecomputer-implemented method of claim 14, wherein the signal comprises agrant to allow transitioning the network device from the running powerstate to the second power state.
 16. The computer-implemented method ofclaim 14, wherein receiving the signal comprises receiving a MAP withthe signal embedded in the MAP.
 17. The computer-implemented method ofclaim 14, further comprising: receiving a beacon signal; andtransitioning, in response to receiving the beacon signal, the networkdevice to the running power state from one of the idle mode or theactive mode.
 18. The computer-implemented method of claim 14, whereinmaintaining a link to a network while powering down a portion of thenetwork device when the network device is in the idle mode.
 19. Thecomputer-implemented method of claim 14, further comprising receiving abeacon signal when the network device is in one of the idle mode or theactive mode.
 20. The computer-implemented method of claim 14, furthercomprising participating in a link maintenance operation (LMO) when thenetwork device is in the active mode.